In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
NFSD: Prevent post-shutdown use-after-free in unlock_filesystem<\/p>\n
Writing a filesystem path to \/proc\/fs\/nfsd\/unlock_filesystem runs
\nnfsd4_cancel_copy_by_sb() before nfsd_mutex is held and before the
\nhandler confirms that nn->nfsd_serv is set. Once nfsd has shut down,
\nnfs4_state_destroy_net() has freed nn->conf_id_hashtbl but left the
\npointer intact, so the cancel helper iterates freed slab memory as an
\narray of struct list_head and then dereferences a bogus nfs4_client
\nwhen it takes clp->async_lock. A local administrator holding
\nCAP_SYS_ADMIN can reach this use-after-free by stopping the server and
\nthen writing to unlock_filesystem; KASAN reports a slab-use-after-free
\nread in nfsd4_cancel_copy_by_sb().<\/p>\n
nfsd4_revoke_states() walks the same state tables and for that reason
\nalready runs only under nfsd_mutex with nn->nfsd_serv confirmed
\npresent. Move the async COPY cancel into that protected section so
\nevery NFSv4 state-table walker on this path observes a running server.
\nAsync copies exist only while the server runs, so gating the cancel on
\nnn->nfsd_serv loses nothing.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
NFSD: Prevent post-shutdown use-after-free in unlock_filesystem<\/p>\n
Writing a filesystem path to \/proc\/fs\/nfsd\/unlock_filesystem runs<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21583","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21583","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21583"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21583"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21583"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}